1. Field of the Invention (Technical Field)
The present invention relates to displays and more particularly to video display processing of deflection based raster signals.
2. Background Art
Conversion of analog display presentation, in an analog deflection based video system for a cathode ray tube (CRT) type display, allows the position and size of the image to be determined strictly by the deflection amplitudes and offsets. Many legacy display systems use horizontal and vertical deflection signals to provide position and scaling in conjunction with another signal, bright-up, or video to provide intensity for video images on CRTs. The problem occurs when these legacy display systems migrate to digital display technology. The size and position of a video image, in a general sense, on normal monitors and digital display systems is based on the timing relationship of synchronization signal characteristics. This is due to the video standard definitions of synchronization and blanking timing that govern the image boundaries and position.
The problem is that video position is based on deflection waveforms for older analog displays. The input horizontal and vertical deflection signals are modified by the image source to change the video presentation and appearance characteristics in position, size, and scale. The conversion of video to time based systems loses the video positional scaling and dimensional information. This can lead to positional inaccuracies of the video presentation when digitally sampled and displayed.
U.S. Pat. No. 5,099,179, entitled “Remote Raster/Stroke Display Calibration” describes a remote registration and calibration system for a hybrid video display. However, this device differs substantially in that it is a one-time calibration to compensate for receiver circuit offset and errors.